Building Blocks
Sexagenary Cycle
The sixty stem-and-branch combinations used to label years, months, days, and hours.
Sixty Jiazi
The sexagenary cycle is the set of sixty unique combinations formed by pairing the ten Heavenly Stems with the twelve Earthly Branches by matching polarity — which is why there are sixty, not one hundred and twenty. It is used to label years, months, days, and two-hour periods, and each pillar of a BaZi chart is one of these stem-branch pairs. The cycle is a well-attested calendrical framework that long predates its use in chart reading.